The subject matter disclosed herein generally relates to a shot sleeve for a die casting process and, more particularly, to oxidation resistant shot sleeves for high temperature die casting.
A die casting process utilizes a mold cavity defined between mold parts. Molten metal material is fed into the mold cavity and held under pressure until the metal hardens. The mold parts are then separated and the cast part removed. In some processes a shot sleeve is utilized to receive molten material from a metal melting source and introduce that material to the cavity. The shot sleeve includes an opening for introducing molten material into a bore of the shot sleeve that leads to the mold cavity. A plunger or piston moves within the bore of the shot sleeve to push the molten material through the shot sleeve and inject the molten material into the mold cavity. The piston is subsequently withdrawn and additional material can be introduced into the bore for fabricating another part within the same mold cavity, i.e., the shot sleeve is reused for multiple molding operations (e.g., die casting operations).
The shot sleeve can experience very high temperatures due to the molten metal material that is passed through the bore of the shot sleeve. Accordingly, the shot sleeve and/or components thereof are fabricated of materials compatible with such high temperatures. However, materials that are compatible with the high temperatures encountered during the die casting process can be costly and difficult to machine. Further, materials that are compatible with the high temperatures may result in shot sleeves with relatively low life cycles. That is, the high temperatures can lead to failure of the shot sleeves, even when the shot sleeve is formed from high temperature materials. Single crystal nickel-based alloys have been proposed for use in shot sleeves. However, uncontrolled oxidation of the single crystal nickel-based alloy can result in issues and decreased shot sleeve life. Oxidation can occur whenever the temperature of the shot sleeve is exposed to oxygen at a sufficient temperature. Accordingly, it is desirable to design and develop shot sleeves that can withstand the high temperatures and are resistant to oxidation.